1. Field of the Invention
The present invention relates to high foaming oral compositions containing an antibacterial compound for the inhibition of bacterial plaque accumulation on dental tissue and more particularly to such compositions containing an antibacterial compound and a mixed anionic/nonionic surfactant system which promotes significantly higher uptake of the antibacterial compound on dental tissue.
2. The Prior Art
Dental plaque is a soft deposit which forms on teeth and is comprised of an accumulation of bacteria and bacterial by-products. Plaque adheres tenaciously at the points of irregularity or discontinuity, e.g., on rough calculus surfaces, at the gum line and the like. Besides being unsightly, plaque is implicated in the occurrence of gingivitis and other forms of periodontal disease.
A wide variety of antibacterial agents have been suggested in the art to retard plaque formation and the oral infections and dental disease associated with plaque formation. For example, halogenated hydroxydiphenyl ether compounds such as triclosan are well known to the art for their antibacterial activity and have been used in oral compositions to counter plaque formation by bacterial accumulation in the oral cavity. The effectiveness of the antibacterial agent is dependent upon its delivery to and uptake by teeth and soft tissue areas of the gums.
Surfactants, and particularly anionic surfactants, such as sodium lauryl sulfate (SLS) are conventionally included in oral formulations, to provide solubilization, dispersion, emulsification and wetting of the other ingredients present, especially flavor oils. Further, surfactants provide a cosmetic effect in promoting the foaming of the oral composition. Oral compositions with strong foaming ability are preferred by consumers, since it is perceived that the greater the foaming, the better the composition cleans the tooth and other oral surfaces, removing stain, plaque and debris therefrom.
U.S. Pat. No. 5,690,911 discloses an oral composition containing an antiplaque halogenated diphenyl ether or phenolic antibacterial agent and a mixed anionic/nonionic surfactant system at a weight ratio of about 14:1 to 9:1 anionic to nonionic surfactant; wherein, the uptake of the antibacterial agent to the dental tissue is increased to enhance the therapeutic efficacy of the administered antibacterial agent. Further, U.S. Pat. No. 5,690,911 further discloses that increasing the ratio of nonionic surfactant will lead to an unacceptable consumer taste. The working examples of U.S. Pat. No. 5,690,911 demonstrate that the optimum uptake of antibacterial agent occurs at approximately a 9:1 anionic to nonionic surfactant weight ratio, when the total amount of surfactant present in the oral composition ranges from about 1.3 to about 1.5% by weight. Unexpectedly, as will be demonstrated below, as the total level of surfactant is increased from 1.5% by weight to about 3.0%, the optimum uptake of antibacterial agent occurs at a significantly lower anionic to nonionic ratio.
There is a need in the art to provide means whereby the delivery to and uptake by dental tissue of antibacterial compounds may be increased to further to enhance the therapeutic efficacy of the antibacterial agent.